The present invention relates to an apparatus for effectively making the supply of material liquid and relief of pressure of reaction product liquid in high-pressure liquefaction reaction process.
A conventional direct liquefaction process for coal will be explained hereinunder. A material slurry supplied to the slurry tank is delivered by a high-pressure slurry pump to a high-pressure reaction vessel. The slurry liquefied in this high-pressure reaction vessel is discharged to the outside of the system through a reducing valve. In this case, the product slurry after the reaction is a high-pressure slurry containing product oil, unliquified coal, ash content and heavy metals. The taking out of the product, i.e. pressure release of the high-pressure product slurry, is made through a reducing valve. The product slurry is relieved from the high pressure taking a form of a continuous jet flow, causing a rapid wear of the valve thus shortening the life of the latter. Since the high pressure of the product slurry is relieved as the slurry is jetted through the reducing valve which acts as a throttling valve, the pressure energy is lost and the power or energy is not recovered.
In addition, in this known system, the slurry pump is required to transport the material slurry of a high concentration at a high pressure, imposing various technical difficulties.
The invention aims at obviating the above-stated problems or shortcomings of the prior art which can be summarized as follows.
(1) Since the reaction is made at a high pressure, it is necessary to transport the slurry at a high pressure, which in turn necessitates a slurry pump operable at the high pressure.
(2) Since the pressure relief of the product slurry discharged from the reaction vessel is made by discharging the slurry as a continuous jet through a pressure reducing valve, wear of the pressure reducing valve grows rapidly.
(3) Since the pressure of the product slurry is lowered as the slurry flows through the pressure reducing valve, the energy possessed by the product slurry of the high pressure is lost without being recovered.
As a result of an intense study for obviating these problems, the present inventors have found out that the high-pressure slurry pump can be eliminated by feeding the material slurry into the reaction vessel making use of the energy possessed by the high-pressure product slurry discharged from the reaction vessel. The pressure of the product slurry is relieved after the energy of the pressure is effectively used for forcibly feeding the material slurry into the reaction vessel. In this manner, the product slurry can be collected as a low-pressure slurry, and the continuous jetting flow of the product slurry, which would cause a rapid wear of the pressure reducing valve, does not take place.